1. Field of the Invention
The present invention relates to a golf club head with a major body composed of a metal material, and a minor body composed of a light-weight material. More specifically, the present invention relates to a golf club head with a major body composed of a metal material for a more efficient transfer of energy to a golf ball at impact, and a non-metallic minor body to control the mass distribution.
2. Description of the Related Art
When a golf club head strikes a golf ball, large impacts are produced that load the club head face and the golf ball. Most of the energy is transferred from the head to the golf ball, however, some energy is lost as a result of the collision. The golf ball is typically composed of polymer cover materials (such as ionomers) surrounding a rubber-like core. These softer polymer materials having damping (loss) properties that are strain and strain rate dependent which are on the order of 10–100 times larger than the damping properties of a metallic club face. Thus, during impact most of the energy is lost as a result of the high stresses and deformations of the golf ball (0.001 to 0.20 inch), as opposed to the small deformations of the metallic club face (0.025 to 0.050 inch). A more efficient energy transfer from the club head to the golf ball could lead to greater flight distances of the golf ball.
The generally accepted approach has been to increase the stiffness of the club head face to reduce metal or club head deformations. However, this leads to greater deformations in the golf ball, and thus increases in the energy transfer problem.
Some have recognized the problem and disclosed possible solutions. An example is Campau, U.S. Pat. No. 4,398,965, for a Method Of Making Iron Golf Clubs With Flexible Impact Surface, which discloses a club having a flexible and resilient face plate with a slot to allow for the flexing of the face plate. The face plate of Campau is composed of a ferrous material, such as stainless steel, and has a thickness in the range of 0.1 inches to 0.125 inches.
Another example is Eggiman, U.S. Pat. No. 5,863,261, for a Golf Club Head With Elastically Deforming Face And Back Plates, which discloses the use of a plurality of plates that act in concert to create a spring-like effect on a golf ball during impact. A fluid is disposed between at least two of the plates to act as a viscous coupler.
Yet another example is Jepson et al, U.S. Pat. No. 3,937,474, for a golf Club With A Polyurethane Insert. Jepson discloses that the polyurethane insert has a hardness between 40 and 75 shore D.
Still another example is Inamori, U.S. Pat. No. 3,975,023, for a Golf Club Head With Ceramic Face Plate, which discloses using a face plate composed of a ceramic material having a high energy transfer coefficient, although ceramics are usually harder materials. Chen et al., U.S. Pat. No. 5,743,813 for a Golf Club Head, discloses using multiple layers in the face to absorb the shock of the golf ball. One of the materials is a non-metal material.
Lu, U.S. Pat. No. 5,499,814, for a Hollow Club Head With Deflecting Insert Face Plate, discloses a reinforcing element composed of a plastic or aluminum alloy that allows for minor deflecting of the face plate which has a thickness ranging from 0.01 to 0.30 inches for a variety of materials including stainless steel, titanium, KEVLAR®, and the like. Yet another Campau invention, U.S. Pat. No. 3,989,248, for a Golf Club Having Insert Capable Of Elastic Flexing, discloses a wood club composed of wood with a metal insert.
Although not intended for flexing of the face plate, Viste, U.S. Pat. No. 5,282,624 discloses a golf club head having a face plate composed of a forged stainless steel material and having a thickness of 3 mm. Anderson, U.S. Pat. No. 5,344,140, for a Golf Club Head And Method Of Forming Same, also discloses use of a forged material for the face plate. The face plate of Anderson may be composed of several forged materials including steel, copper and titanium. The forged plate has a uniform thickness of between 0.090 and 0.130 inches.
Another invention directed toward forged materials in a club head is Su et al., U.S. Pat. No. 5,776,011 for a Golf Club Head. Su discloses a club head composed of three pieces with each piece composed of a forged material. The main objective of Su is to produce a club head with greater loft angle accuracy and reduce structural weaknesses. Aizawa, U.S. Pat. No. 5,346,216 for a Golf Club Head, discloses a face plate having a curved ball hitting surface.
U.S. Pat. No. 6,146,571 to Vincent, et al., discloses a method of manufacturing a golf club head wherein the walls are obtained by injecting a material such as plastic over an insert affixed to a meltable core. The core has a melt point lower than that of the injectable plastic material so that once the core is removed, an inner volume is maintained to form the inner cavity. The insert may comprise a resistance element for reinforcing the internal portion of the front wall of the shell upon removal of the core where the reinforcement element is comprised of aluminum with a laterally extending portion comprised of steel.
U.S. Pat. No. 6,149,534 to Peters, et al., discloses a golf club head having upper and lower metal engagement surfaces formed along a single plane interface wherein the metal of the lower surface is heavier and more dense than the metal of the upper surface.
U.S. Pat. Nos. 5,570,886 and 5,547,427 to Rigal, et al., disclose a golf club head of molded thermoplastic having a striking face defined by an impact-resistant metallic sealing element. The sealing element defines a front wall of the striking surface of the club head and extends upward and along the side of the impact surface to form a neck for attachment of the shaft to the club head. The sealing element preferably being between 2.5 and 5 mm in thickness.
U.S. Pat. No. 5,425,538 to Vincent, et al., discloses a hollow golf club head having a steel shell and a composite striking surface composed of a number of stacked woven webs of fiber.
U.S. Pat. No. 5,377,986 to Viollaz, et al., discloses a golf club head having a body composed of a series of metal plates and a hitting plate comprised of plastic or composite material wherein the hitting plate is imparted with a forwardly convex shape. Additionally, U.S. Pat. No. 5,310,185 to Viollaz, et al., discloses a hollow golf club head having a body composed of a series of metal plates, a metal support plate being located on the front hitting surface to which a hitting plate comprised of plastic or composite is attached. The metal support plate has a forwardly convex front plate associated with a forwardly convex rear plate of the hitting plate thereby forming a forwardly convex hitting surface.
U.S. Pat. No. 5,106,094 to Desboilles, et al., discloses a golf club head having a metal striking face plate wherein the striking face plate is a separate unit attached to the golf club head with a quantity of filler material in the interior portion of the club head.
U.S. Pat. No. 4,568,088 to Kurahashi discloses a wooden golf club head body reinforced by a mixture of wood-plastic composite material. The wood-plastic composite material being unevenly distributed such that a higher density in the range of between 5 and 15 mm lies adjacent to and extends substantially parallel with the front face of the club head.
U.S. Pat. No. 4,021,047 to Mader discloses a golf club wherein the sole plate, face plate, heel, toe and hosel portions are formed as a unitary cast metal piece and wherein a wood or composite crown is attached to this unitary piece thereby forming a hollow chamber in the club head.
U.S. Pat. No. 5,624,331 to Lo, et al. discloses a hollow metal golf club head where the metal casing of the head is composed of at least two openings. The head also contains a composite material disposed within the head where a portion of the composite material is located in the openings of the golf club head casing.
U.S. Pat. No. 1,167,387 to Daniel discloses a hollow golf club head wherein the shell body is comprised of metal such as aluminum alloy and the face plate is comprised of a hard wood such as beech, persimmon or the like. The face plate is aligned such that the wood grain presents endwise at the striking plate.
U.S. Pat. No. 3,692,306 to Glover discloses a golf club head having a bracket with sole and striking plates formed integrally thereon. At least one of the plates has an embedded elongate tube for securing a removably adjustable weight means.
U.S. Pat. No. 5,410,798 to Lo discloses a method of manufacturing a composite golf club head using a metal casing to which a laminated member is inserted. A sheet of composite material is subsequently layered over the openings of the laminated member and metal casing to close off the openings in the top of both. An expansible pocket is then inserted into the hollow laminated member comprising sodium nitrite, ammonium chloride and water causing the member to attach integrally to the metal casing when the head is placed into a mold and heated.
U.S. Pat. No. 4,877,249 to Thompson discloses a wood golf club head embodying a laminated upper surface and metallic sole surface having a keel. In order to reinforce the laminations and to keep the body from delaminating upon impact with an unusually hard object, a bolt is inserted through the crown of the club head where it is connected to the sole plate at the keel and tightened to compress the laminations.
U.S. Pat. No. 3,897,066 to Belmont discloses a wooden golf club head having removably inserted weight adjustment members. The members are parallel to a central vertical axis running from the face section to the rear section of the club head and perpendicular to the crown to toe axis. The weight adjustment members may be held in place by the use of capsules filled with polyurethane resin, which can also be used to form the faceplate. The capsules have openings on a rear surface of the club head with covers to provide access to adjust the weight means.
U.S. Pat. No. 2,750,194 to Clark discloses a wooden golf club head with weight adjustment means. The golf club head includes a tray member with sides and bottom for holding the weight adjustment preferably cast or formed integrally with the heel plate. The heel plate with attached weight member is inserted into the head of the golf club via an opening.
U.S. Pat. No. 5,193,811 to Okumoto, et al. discloses a wood type club head body comprised primarily of a synthetic resin and a metallic sole plate. The metallic sole plate has on its surface for bonding with the head body integrally formed members comprising a hosel on the heel side, weights on the toe and rear sides and a beam connecting the weights and hosel. Additionally, U.S. Pat. No. 5,516,107 to Okumoto, et al., discloses a golf club head having an outer shell, preferably comprised of synthetic resin, and metal weight member/s located on the interior of the club head. A foamable material is injected into the hollow interior of the club to form the core. Once the foamable material has been injected and the sole plate is attached, the club head is heated to cause the foamable material to expand thus holding the weight member/s in position in recess/es located in toe, heel and/or back side regions by pushing the weight member into the inner surface of the outer shell.
U.S. Pat. No. 4,872,685 to Sun discloses a wood type golf club head wherein a female unit is mated with a male unit to form a unitary golf club head. The female unit comprises the upper portion of the golf club head and is preferably composed of plastic, alloy, or wood. The male unit includes the structural portions of sole plate, a face insert consists of the striking plate and weighting elements. The male unit has a substantially greater weight being preferably composed of a light metal alloy. The units are mated or held together by bonding and or mechanical means.
U.S. Pat. No. 5,398,935 to Katayama discloses a wood golf club head having a striking face wherein the height of the striking face at a toe end of the golf club head is nearly equal to or greater than the height of the striking face at the center of the club head.
U.S. Pat. No. 1,780,625 to Mattern discloses a club head with a rear portion composed of a light-weight metal such as magnesium. U.S. Pat. No. 1,638,916 to Butchart discloses a golf club with a balancing member composed of persimmon or a similar wood material, and a shell-like body composed of aluminum attached to the balancing member.
The Rules of Golf, established and interpreted by the United States Golf Association (“USGA”) and The Royal and Ancient Golf Club of Saint Andrews, set forth certain requirements for a golf club head. The requirements for a golf club head are found in Rule 4 and Appendix II. A complete description of the Rules of Golf are available on the USGA web page at www.usga.org. Although the Rules of Golf do not expressly state specific parameters for a golf club face, Rule 4-1e prohibits the face from having the effect at impact of a spring with a golf ball. In 1998, the USGA adopted a test procedure pursuant to Rule 4-1e which measures club face COR. This USGA test procedure, as well as procedures like it, may be used to measure club face COR.
Sound, or specifically sound waves are longitudinal mechanical waves that compress a medium such as air to stimulate the human ear and brain for the sensation of hearing. The frequency range that can stimulate the human ear for hearing is designated the audible range and ranges from 20 Hertz (cycles) to 20,000 Hertz. The sound waves create a pressure that varies depending on the medium, the frequency and distance. The human ear can tolerate a sound pressure of 28 Pascals, and can detect a sound pressure as low as 2.0.times.10−5 Pascals. Sound, or the sound level, is measured in decibels (named after Alexander Graham Bell), and is a parameter related to the intensity of a sound wave according to the following equation:SPL=10 log10(I/Io)wherein I is the intensity and Io is a standard reference intensity (Io=10−12 W/m2). The intensity I may be found from the pressure amplitude wherein the average intensity I=(1/2)Pm2/v wherein Pm=the pressure amplitude of the sound in air, v=the velocity of sound in air, and o=the density of air. When I=Io, the sound level is zero decibels which is the threshold of hearing. For reference, a whisper is twenty decibels, normal conversation is sixty decibels, a pneumatic drill at a distance of three meters has a sound level of ninety decibels, and a jet engine at fifty meters has a sound level of one hundred thirty decibels. A golf club striking a golf ball will emit certain sound levels according to the material and construction of the golf club.
Golfers have become accustomed to hearing a particular sound when the club face impacts the golf ball, especially when a driver or fairway wood is used by the golfer. This “sound expectation” has grown tremendously since the introduction of hollow metal woods. This particular sound imparts a sensation to the golfer of a good shot, a quality club or both.
The sound expectation from a metal wood has become so entrenched that woods lacking this particular sound are believed to be inferior or are undesired by golfers. This sound expectation has greatly effected multiple material, large volume golf clubs since current multiple material, large volume golf clubs have an undesirable tone.
Further, the current manufacturers of multiple material, large volume (over 350 cc) golf clubs have had no desire to improve the sound since improving the performance and lowering the costs of these golf clubs have been the major design concerns of such manufacturers. Thus, although the performance and price of multiple material, large volume golf clubs have improved, the sound has remained unchanged and is an obstacle to increased acceptance of multiple material, large volume golf clubs.
Although the prior art has disclosed many variations of multiple material club heads, the prior art has failed to provide a multiple material, large volume club head with a sufficient volume and an appealing sound during impact with a golf ball.